A seat reclining apparatus for a vehicle disclosed in JP2003312329A includes a rail member, a slider, a lock apparatus and a striker. The rail member is attached to a vehicle body and is formed in a circular arc shape to be aligned along a curve described by the seat back upon its reclining operation, the slider is engaged with the rail member so as to be slidable thereon, the lock apparatus regulates/permits the slider sliding on the rail member, and the striker is fixed on the slider. In this configuration, an angle of the seat back is maintained when the striker is engaged with a lock member attached to the seat back.
Further, a seat reclining apparatus for a vehicle disclosed in JP2003054299A basically has the same configuration as that of JP2003312329A. Specifically, in JP2003054299A, the rail member is formed in a straight shape and positioned so as to be approximately aligned along the curve described by the seat back upon its reclining operation. In this configuration, a gap existing between the lock member making pivotal movement and the striker moving straight, in other words, a gap existing in a radial direction of the rotation of the lock member, is adjusted.
In JP2003312329A, a positional error may occur between the rail member attached to a side surface of the vehicle body and the rotational center of the seat back set on the vehicle floor, and such error may affect on locking performance of the lock apparatus and slide resistance generated between the rail member and the slider. However, because the number of parts provided between the vehicle floor and the side surface of the vehicle is large, and most of the parts are mounted to the vehicle by welding, positions of the parts may not be accurate, as a result, the level of accuracy of the rotational center of the seat back may not be enhanced. Further, because a shape of the seat back may not be accurate, and the number of parts structuring the lock member is large, a strain may occur at the vehicle seat. Furthermore, manufacturing the rail member whose shape is an arc is difficult.
Accordingly, the slider may not slide on the rail member smoothly, and rattle may occur between the rail member and the slider. In JP2003312329A, any measure for those matters is not suggested. Furthermore, in JP2003054299A, because of the structure of the apparatus, a gap existing between the lock member making pivotal movement and the striker moving straight needs to be adjusted. In this case, even when the gap is adjusted, a small gap still needs to be provided between the lock member and the striker so that the striker may smoothly slide on the lock member. However, because of the small gap between the lock member and the striker, the seat back may be insecure in a direction of tilting movement thereof, as a result, the level of quality of the seat slide apparatus may be reduced. Further, when the gap is adjusted, resistance may be generated between the lock member and the striker, and a positional error may occur in the same manner as that in JP2003312329A.
A need thus exists for a seat reclining apparatus for vehicle which is not susceptible to the drawback mentioned above.